/*=========================================================================
 *
 *  Copyright Insight Software Consortium
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *         http://www.apache.org/licenses/LICENSE-2.0.txt
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *=========================================================================*/
#ifndef __itkTestingExtractSliceImageFilter_hxx
#define __itkTestingExtractSliceImageFilter_hxx

#include "itkTestingExtractSliceImageFilter.h"
#include "itkImageRegionIterator.h"
#include "itkObjectFactory.h"
#include "itkProgressReporter.h"

namespace itk
{
namespace Testing
{
/**
 *
 */
template <class TInputImage, class TOutputImage>
ExtractSliceImageFilter<TInputImage, TOutputImage>
::ExtractSliceImageFilter() :
#ifdef ITKV3_COMPATIBILITY
  m_DirectionCollaspeStrategy(DIRECTIONCOLLAPSETOGUESS)
#else
  m_DirectionCollaspeStrategy(DIRECTIONCOLLAPSETOUNKOWN)
#endif
{
}

/**
 *
 */
template <class TInputImage, class TOutputImage>
void
ExtractSliceImageFilter<TInputImage, TOutputImage>
::PrintSelf(std::ostream & os, Indent indent) const
{
  Superclass::PrintSelf(os, indent);

  os << indent << "ExtractionRegion: " << m_ExtractionRegion << std::endl;
  os << indent << "OutputImageRegion: " << m_OutputImageRegion << std::endl;
  os << indent << "DirectionCollaspeStrategy: " << m_DirectionCollaspeStrategy << std::endl;
}

template <class TInputImage, class TOutputImage>
void
ExtractSliceImageFilter<TInputImage, TOutputImage>
::CallCopyOutputRegionToInputRegion(InputImageRegionType & destRegion,
                                    const OutputImageRegionType & srcRegion)
{
  ExtractSliceImageFilterRegionCopierType extractImageRegionCopier;

  extractImageRegionCopier(destRegion, srcRegion, m_ExtractionRegion);
}

template <class TInputImage, class TOutputImage>
void
ExtractSliceImageFilter<TInputImage, TOutputImage>
::SetExtractionRegion(InputImageRegionType extractRegion)
{
  m_ExtractionRegion = extractRegion;

  unsigned int        nonzeroSizeCount = 0;
  InputImageSizeType  inputSize = extractRegion.GetSize();
  OutputImageSizeType outputSize;
  outputSize.Fill(0);
  OutputImageIndexType outputIndex;
  outputIndex.Fill(0);
  /**
   * check to see if the number of non-zero entries in the extraction region
   * matches the number of dimensions in the output image.
   */
  for( unsigned int i = 0; i < InputImageDimension; ++i )
    {
    if( inputSize[i] )
      {
      outputSize[nonzeroSizeCount] = inputSize[i];
      outputIndex[nonzeroSizeCount] = extractRegion.GetIndex()[i];
      nonzeroSizeCount++;
      }
    }

  if( nonzeroSizeCount != OutputImageDimension )
    {
    itkExceptionMacro("Extraction Region not consistent with output image");
    }

  m_OutputImageRegion.SetSize(outputSize);
  m_OutputImageRegion.SetIndex(outputIndex);
  this->Modified();
}

/**
 * ExtractSliceImageFilter can produce an image which is a different resolution
 * than its input image.  As such, ExtractSliceImageFilter needs to provide an
 * implementation for GenerateOutputInformation() in order to inform
 * the pipeline execution model.  The original documentation of this
 * method is below.
 *
 * \sa ProcessObject::GenerateOutputInformaton()
 */
template <class TInputImage, class TOutputImage>
void
ExtractSliceImageFilter<TInputImage, TOutputImage>
::GenerateOutputInformation()
{
  // do not call the superclass' implementation of this method since
  // this filter allows the input and the output to be of different dimensions

  // get pointers to the input and output
  TOutputImage *      outputPtr = this->GetOutput();
  const TInputImage * inputPtr  = this->GetInput();

  if( !outputPtr || !inputPtr )
    {
    return;
    }

  // Set the output image size to the same value as the extraction region.
  outputPtr->SetLargestPossibleRegion(m_OutputImageRegion);

  // Set the output spacing and origin
  const ImageBase<InputImageDimension> *phyData;

  phyData =
    dynamic_cast<const ImageBase<InputImageDimension> *>( this->GetInput() );

  if( phyData )
    {
    // Copy what we can from the image from spacing and origin of the input
    // This logic needs to be augmented with logic that select which
    // dimensions to copy

    const typename InputImageType::SpacingType &
    inputSpacing = inputPtr->GetSpacing();
    const typename InputImageType::DirectionType &
    inputDirection = inputPtr->GetDirection();
    const typename InputImageType::PointType &
    inputOrigin = inputPtr->GetOrigin();

    typename OutputImageType::SpacingType outputSpacing;
    typename OutputImageType::DirectionType outputDirection;
    typename OutputImageType::PointType outputOrigin;
    outputOrigin.Fill(0.0);

    if( static_cast<unsigned int>( OutputImageDimension ) >
        static_cast<unsigned int>( InputImageDimension ) )
      {
      // copy the input to the output and fill the rest of the
      // output with zeros.
      for( unsigned int i = 0; i < InputImageDimension; ++i )
        {
        outputSpacing[i] = inputSpacing[i];
        outputOrigin[i] = inputOrigin[i];
        for( unsigned int dim = 0; dim < InputImageDimension; ++dim )
          {
          outputDirection[i][dim] = inputDirection[i][dim];
          }
        }
      for( unsigned int i = InputImageDimension; i < OutputImageDimension; ++i )
        {
        outputSpacing[i] = 1.0;
        outputOrigin[i] = 0.0;
        for( unsigned int dim = 0; dim < InputImageDimension; ++dim )
          {
          outputDirection[i][dim] = 0.0;
          }
        outputDirection[i][i] = 1.0;
        }
      }
    else
      {
      // copy the non-collapsed part of the input spacing and origing to the
      // output
      outputDirection.SetIdentity();
      int nonZeroCount = 0;
      for( unsigned int i = 0; i < InputImageDimension; ++i )
        {
        if( m_ExtractionRegion.GetSize()[i] )
          {
          outputSpacing[nonZeroCount] = inputSpacing[i];
          outputOrigin[nonZeroCount] = inputOrigin[i];
          int nonZeroCount2 = 0;
          for( unsigned int dim = 0; dim < InputImageDimension; ++dim )
            {
            if( m_ExtractionRegion.GetSize()[dim] )
              {
              outputDirection[nonZeroCount][nonZeroCount2] =
                inputDirection[nonZeroCount][dim];
              ++nonZeroCount2;
              }
            }
          nonZeroCount++;
          }
        }
      }

    // if the filter changes from a higher to a lower dimension, or
    // if, after rebuilding the direction cosines, there's a zero
    // length cosine vector, reset the directions to identity.
    switch( m_DirectionCollaspeStrategy )
      {
      case DIRECTIONCOLLAPSETOIDENTITY:
        {
        outputDirection.SetIdentity();
        }
        break;
      case DIRECTIONCOLLAPSETOSUBMATRIX:
        {
        if( vnl_determinant( outputDirection.GetVnlMatrix() ) == 0.0 )
          {
          itkExceptionMacro( << "Invalid submatrix extracted for collapsed direction." );
          }
        }
        break;
      case DIRECTIONCOLLAPSETOGUESS:
        {
        if( vnl_determinant( outputDirection.GetVnlMatrix() ) == 0.0 )
          {
          outputDirection.SetIdentity();
          }
        }
        break;
      case DIRECTIONCOLLAPSETOUNKOWN:
      default:
        {
        itkExceptionMacro( << "It is required that the strategy for collapsing"
                           " the direction matrix be explicitly specified. "
                           "Set with either myfilter->SetDirectionCollapseToIdentity()"
                           " or myfilter->SetDirectionCollapseToSubmatrix() "
                           << typeid( ImageBase<InputImageDimension> * ).name() );
        }
      }

    // set the spacing and origin
    outputPtr->SetSpacing(outputSpacing);
    outputPtr->SetDirection(outputDirection);
    outputPtr->SetOrigin(outputOrigin);
    outputPtr->SetNumberOfComponentsPerPixel(
      inputPtr->GetNumberOfComponentsPerPixel() );
    }
  else
    {
    // pointer could not be cast back down
    itkExceptionMacro( << "itk::ExtractSliceImageFilter::GenerateOutputInformation "
                       << "cannot cast input to "
                       << typeid( ImageBase<InputImageDimension> * ).name() );
    }
}

/**
 * ExtractSliceImageFilter can be implemented as a multithreaded filter.
 * Therefore, this implementation provides a ThreadedGenerateData()
 * routine which is called for each processing thread. The output
 * image data is allocated automatically by the superclass prior to
 * calling ThreadedGenerateData().  ThreadedGenerateData can only
 * write to the portion of the output image specified by the
 * parameter "outputRegionForThread"
 *
 */
template <class TInputImage, class TOutputImage>
void
ExtractSliceImageFilter<TInputImage, TOutputImage>
::ThreadedGenerateData(const OutputImageRegionType & outputRegionForThread,
                       ThreadIdType threadId)
{
  itkDebugMacro(<< "Actually executing");

  // Get the input and output pointers
  const TInputImage * inputPtr = this->GetInput();
  TOutputImage *      outputPtr = this->GetOutput();

  // support progress methods/callbacks
  ProgressReporter progress( this, threadId, outputRegionForThread.GetNumberOfPixels() );

  // Define the portion of the input to walk for this thread
  InputImageRegionType inputRegionForThread;
  this->CallCopyOutputRegionToInputRegion(inputRegionForThread, outputRegionForThread);

  // Define the iterators.
  typedef ImageRegionIterator<TOutputImage>     OutputIterator;
  typedef ImageRegionConstIterator<TInputImage> InputIterator;

  OutputIterator outIt(outputPtr, outputRegionForThread);
  InputIterator  inIt(inputPtr, inputRegionForThread);

  // walk the output region, and sample the input image
  while( !outIt.IsAtEnd() )
    {
    // copy the input pixel to the output
    outIt.Set( static_cast<OutputImagePixelType>( inIt.Get() ) );
    ++outIt;
    ++inIt;
    progress.CompletedPixel();
    }
}

/**
 *
 */
template <class TInputImage, class TOutputImage>
void
ExtractSliceImageFilter<TInputImage, TOutputImage>
::SetInput(const TInputImage *input)
{
  // Process object is not const-correct so the const_cast is required here
  this->ProcessObject::SetNthInput( 0, const_cast<TInputImage *>( input ) );
}

/**
 *
 */
template <class TInputImage, class TOutputImage>
const TInputImage *
ExtractSliceImageFilter<TInputImage, TOutputImage>
::GetInput(void) const
{
  if( this->GetNumberOfInputs() < 1 )
    {
    return 0;
    }

  return static_cast<const TInputImage *>( this->ProcessObject::GetInput(0) );
}
} // end namespace Testing
} // end namespace itk

#endif
